1. Field of the Invention
The present invention generally relates to electronic component packaging, and in particular to packaging which is hermetically sealed.
2. Background Description
It is common in the trade to use hermetic sealing to protect electrical components from deterioration and promote long term viability of the components. There are two commonly employed methods used by the industry to make a hermetically sealed electrical package of this type. For example, components may be encapsulated within a casing using a non-conductive potting material. However, the components inside the package must be covered with a buffer material. Furthermore, there is a long process time to encapsulate the package by transfer molding or by using a liquid encapsulant. Another method of hermetic sealing is to use a header and cover design, and to glue the cover to the header with an adhesive. However, this process needs skilled labor and it takes time to cure the adhesive.
Thus the existing processes are slow and expensive. What is needed is a package design and hermetic sealing method usable in a mass production environment which provides for stable electrical connections to components inside a hermetically sealed container, without use of encapsulation material or an adhesive which take time and skilled labor.
It is therefore an object of the present invention to provide an improved hermetically sealed electrical package for component assemblies.
Another object of the invention is to provide a package design which is efficient to use in mass production of hermetically sealed component assemblies.
It is a further object of the invention to provide a package which can be hermetically sealed with a reduced cost and processing time.
Yet another object of the invention is to avoid the use of encapsulation techniques which require a relatively long process time for transfer molding or for use of a liquid encapsulant.
A further object of the invention is to provide a hermetic sealing method that is efficient in a mass production environment, not requiring skilled labor for the application of adhesives at the seal.
The invention provides a hermetically sealed electrical package having wires entering at the base and being embedded vertically in its walls for connecting to the leads of a component assembly within the package. The wires protrude vertically from the walls, serving as pins for electrical connection to the leads inside the package. The component assembly is secured to an inner side of the package by an adhesive. A cover is affixed to the upper edges of the walls by means of an ultrasonic weld so as to create a hermetic seal.
In a preferred embodiment, the package is a rectangular container having a rectangular floor joined to four walls arranged vertically from the floor, with each wall having two vertical edges and top and bottom horizontal edges, with the bottom horizontal edges being joined to the floor and the vertical edges forming joints between adjacent walls at right angles, with two walls opposite one another being channel walls and the other two walls opposite one another being side walls. The wires for connecting to the component assembly inside the container entering at the floor from outside the container and rise vertically inside a channel wall and terminate in a pin protruding from the top horizontal edge of the channel wall. The electrical component assembly is mounted with adhesive on an inner face of said container, and each of its conducting leads are electrically connected to one of the pins protruding from a channel wall. A cover for the container is joined without application of an adhesive to the top horizontal edges of all of the walls to seal said component assembly hermetically within said container, the cover and walls being of suitable material for bonding using an ultrasonic weld.
In a preferred embodiment of the invention the floor, walls and embedded wires with pins are molded as a unit.